During the last 15 years, eight patients with a diagnosis of hydatid cysts of the heart and one patient with a diagnosis of alveolar hydatid disease with intracardiac parasitic thrombus underwent successful operation at La Pitié Hospital. Only five cases had symptoms, and the remaining four cases were diagnosed incidentally. Serologic tests achieved a variety of results and were not determinant. All patients were examined with echocardiography and angiography, and almost all patients underwent magnetic resonance scanning. Sternotomy was the approach used, and all patients underwent operation with cardiopulmonary bypass. Surgical treatment included puncture and aspiration of the cyst content, previous sterilization with hypertonic saline solution, and excision of the cyst with closure of the cavity in seven patients with different concomitant procedures. No case of intraoperative rupture was reported, and the only complication was an atrioventricular block in a patient with a cyst of the left ventricular wall invading the intraventricular septum. There was no operative mortality, and only one late death was observed. No recurrences or associated complications were reported in the late follow-up.